[Amps] Amps Digest, Vol 57, Issue 52

Wed Sep 26 21:54:09 EDT 2007

Yes Ed
Somebody still cares....
I am an old ham (1968)
Those were the days were the laws of nature still ruled.
And I still have a few nice instruments from those days, --for some reason 
they
still give me the same old readings. I guess they have not got the fact thar 
the rules have changed !
Nils "Peter"  ... Msc MIT --- Oh god why do I still care about that...?
----- Original Message ----- 
From: "Edwin Karl" <edk0kl at centurytel.net>
To: <amps at contesting.com>
Sent: Thursday, September 27, 2007 3:27 AM
Subject: Re: [Amps] Amps Digest, Vol 57, Issue 52


> Re: Amplifier Linearity
>
> Does anyone besides me still use a 'scope in trapezoid pattern looking
> at input vs. output linearity?
>
> Seems like we're getting into "flat topping" tubes, etc just to get the 
> max.
> output level etc.
>
> All the "it can't happen here" talk is really counter productive. If a guy
> says
> he can do it for heaven's sake let it go. Please don't try and prove how
> clever you
> are. It just doesn't impress me and wastes my time.
>
> Thanks
>
> 73
>
> ed K0KL
>
>
> ----- Original Message ----- 
> From: <amps-request at contesting.com>
> To: <amps at contesting.com>
> Sent: Wednesday, September 26, 2007 9:56 AM
> Subject: Amps Digest, Vol 57, Issue 52
>
>
>> Send Amps mailing list submissions to
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>>
>> Today's Topics:
>>
>>    1. Re: IMD (Chris Pedder)
>>    2. Re: How much electrolitic for a HV supply ?
>>       (Peter Frenning [OZ1PIF])
>>    3. Re: How much electrolitic for a HV supply ?
>>       (Hamilton Horta - PY2NI)
>>    4. New SB-200 owner (r2robby)
>>    5. Re: IMD (jeremy-ca)
>>    6. Re: How much electrolitic for a HV supply ?
>>       (Peter Frenning [OZ1PIF])
>>    7. Re: IMD (Steve Katz)
>>    8. Re: IMD (Tom Rauch)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Wed, 26 Sep 2007 14:01:52 +0000
>> From: Chris Pedder <chris at g3vbl.co.uk>
>> Subject: Re: [Amps] IMD
>> To: amps at contesting.com
>> Message-ID: <20070926140305.97747319C5E at dayton.contesting.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> W1QJ wrote:
>>
>>
>> >"AT highways speeds 55-70MPH you are  probably using
>> >less than a third of the total HP.  I guess it is kinda the  same thing
>> >HUH?"
>>
>>
>> Forgive me, but I don't understand where your figure of 'a third' comes
> from.
>>
>> Is it something that "makes sense to you" and is this how you decided
>> it was "right" for you?
>>
>> Chris
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Wed, 26 Sep 2007 15:35:34 +0200
>> From: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
>> Subject: Re: [Amps] How much electrolitic for a HV supply ?
>> To: Hamilton Horta - PY2NI <py2ni at terra.com.br>
>> Cc: amps at contesting.com
>> Message-ID: <46FA6026.7090006 at frenning.dk>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Hamilton Horta - PY2NI skrev:
>> >     Hi everybody, is there any rule of thumb or whatever to determine
> the
>> > minimum
>> > amount of electrolitic caps should one put in a HV power supply?
>> >     I am building a VHF PA with 1x GI-7B @ 2200V and another for a
> friend of
>> > mine with 2xGI-7B, I know that we are usually biased to use as much as
>> > possible but I am really eager to know the minimum for these two amps
>> > running 1xGI-7B and one with 2xGI-7B both operating at 2200V.
>> >
>> > Thanks a lot.
>> >
>> >
>> Hi Horta,
>> It's mostly a question of availability of suitable Caps. A well suited
>> common type is 450V/220uF, you could get by with 6 in series, but that
>> is cutting it very close, prudence would say use 8 in series giving a
>> reasonable margin on V and some 27.5uF - that'll do at least up to 500mA
>> and likely substantially more.
>> I'm using this configuration in both a 2200V supply for a Gi7b (144MHz)
>> and a 3000V supply for a QB-4/1100 (HF), both has given trouble-free
>> operation for several years and good reports on audio quality.
>>
>> -- 
>> Vy 73 de OZ1PIF/5Q2M, Peter
>>
>> ** CW: Who? Me? You must be joking!! **
>> email: peter(no-spam-filler)@frenning.dk
>> http://www.frenning.dk/oz1pif.htm
>> Ph. +45 4619 3239
>> Snailmail:
>> Peter Frenning
>> Ternevej 23
>> DK-4130 Viby Sj.
>> Denmark
>> ***********************************
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Wed, 26 Sep 2007 11:12:28 -0300
>> From: "Hamilton Horta - PY2NI" <py2ni at terra.com.br>
>> Subject: Re: [Amps] How much electrolitic for a HV supply ?
>> To: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
>> Cc: amps at contesting.com
>> Message-ID: <02ef01c80047$45af8d30$6501a8c0 at NABLA>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>>     Thanks a lot Peter, these figures are very close to what I thought,
>> actually
>> I was tempted to try (not in a definitive way but just run some tests)
> with
>> something around 6,7uF (7x 47uF in parallel) but only for the amp with
> just
>> one GI-7B. My feeling is that it?s going to prove me  I am wrong :)
>>
>> 73
>> Horta
>> PY2NI
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
>> To: "Hamilton Horta - PY2NI" <py2ni at terra.com.br>
>> Cc: <amps at contesting.com>
>> Sent: Wednesday, September 26, 2007 10:35 AM
>> Subject: Re: [Amps] How much electrolitic for a HV supply ?
>>
>>
>> > Hamilton Horta - PY2NI skrev:
>> > >     Hi everybody, is there any rule of thumb or whatever to determine
>> the
>> > > minimum
>> > > amount of electrolitic caps should one put in a HV power supply?
>> > >     I am building a VHF PA with 1x GI-7B @ 2200V and another for a
>> friend of
>> > > mine with 2xGI-7B, I know that we are usually biased to use as much 
>> > > as
>> > > possible but I am really eager to know the minimum for these two amps
>> > > running 1xGI-7B and one with 2xGI-7B both operating at 2200V.
>> > >
>> > > Thanks a lot.
>> > >
>> > >
>> > Hi Horta,
>> > It's mostly a question of availability of suitable Caps. A well suited
>> > common type is 450V/220uF, you could get by with 6 in series, but that
>> > is cutting it very close, prudence would say use 8 in series giving a
>> > reasonable margin on V and some 27.5uF - that'll do at least up to 
>> > 500mA
>> > and likely substantially more.
>> > I'm using this configuration in both a 2200V supply for a Gi7b (144MHz)
>> > and a 3000V supply for a QB-4/1100 (HF), both has given trouble-free
>> > operation for several years and good reports on audio quality.
>> >
>> > --
>> > Vy 73 de OZ1PIF/5Q2M, Peter
>> >
>> > ** CW: Who? Me? You must be joking!! **
>> > email: peter(no-spam-filler)@frenning.dk
>> > http://www.frenning.dk/oz1pif.htm
>> > Ph. +45 4619 3239
>> > Snailmail:
>> > Peter Frenning
>> > Ternevej 23
>> > DK-4130 Viby Sj.
>> > Denmark
>> > ***********************************
>> >
>> >
>> > Esta mensagem foi verificada pelo E-mail Protegido Terra.
>> > Scan engine: McAfee VirusScan / Atualizado em 25/09/2007 / Vers?o:
>> 5.1.00/5127
>> > Proteja o seu e-mail Terra: http://mail.terra.com.br/
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>> >
>> > --
>> > No virus found in this incoming message.
>> > Checked by AVG Free Edition.
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>> 25/9/2007 08:02
>> >
>> >
>>
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Wed, 26 Sep 2007 11:21:43 -0300
>> From: "r2robby" <robby at route2.pe.ca>
>> Subject: [Amps] New SB-200 owner
>> To: <amps at contesting.com>
>> Message-ID: <002b01c80048$952f27c0$bf8d7740$@pe.ca>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> I am a new subscriber to this list and soon to be an ex-subscriber.
>>
>>
>>
>> I have recently bought a used SB-200 and plan on converting it to 6M
>> monoband use.  I do not plan to pay someone to do it even thought they
> might
>> do a better job.
>>
>>
>>
>> I thought I would get some useful information on this reflector.  Not so
>> far!
>>
>>
>>
>> When I signed up I was presented with the following information about the
>> list:
>>
>>
>>
>> Welcome to the Amplifier mailing list! This list is intended for the
>> exchange of information on HAM RADIO Amplifiers related topics ONLY. Our
>> goal is to keep Amplifier information content high and noise low.
>>
>> DO NOT USE THIS REFLECTOR TO POST COMPLAINTS, PERSONAL CRITICISMS OR
>> ATTACKS, AND DISCUSSIONS OF LIST OPERATION, ETC. VIOLATORS OF THIS POLICY
>> WILL BE REMOVED IMMEDIATELY WITHOUT NOTICE.
>>
>> Be considerate of other subscribers who have bandwidth limitations and
> edit
>> posts for succinctness (include ONLY relevant excerpts of previous 
>> posts).
>> NOTE: Top-posting complete previous messages are not allowed...please
> either
>> edit relevant parts of prior messages or delete them entirely. When
>> responding to a specific individual, think carefully before copying to 
>> the
>> other 1100 of us on the reflector.
>>
>> Minimize noise, minimize bandwidth, maximize Amplifier information, act
> like
>> gentlemen and enjoy!
>>
>>
>>
>> I thought it might be useful for some of you to read it again.
>>
>> If I am not able to get at any information that will benefit my project 
>> on
>> this list, could someone kindly direct me to the correct one.
>>
>> Thanks in advance,
>>
>> 73,
>>
>> -Robby
>> VY2SS
>>
>> Friendship is like peeing your pants,
>> everyone can see it,
>> but only you can feel the true warmth.
>>
>>
>>
>> ------------------------------
>>
>> Message: 5
>> Date: Wed, 26 Sep 2007 10:29:33 -0400
>> From: "jeremy-ca" <km1h at jeremy.mv.com>
>> Subject: Re: [Amps] IMD
>> To: "k7fm" <k7fm at teleport.com>, <Gudguyham at aol.com>
>> Cc: amps at contesting.com
>> Message-ID: <00b001c80049$ab1a0180$6500a8c0 at KITTYMA123>
>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>> reply-type=original
>>
>> Thats a bunch of BS as usual from you.
>>
>> Any decent commercial amp will do more than its advertised at. Its called
>> overhead and allows for tube aging. Using you distorted logic (pun
> intended)
>> an AL-1500 cant be run over 1500W otherwise you will have a poor signal.
>>
>> Since you appear to be an expert please explain how YOU would tune up a 
>> GG
>> amp for best linearity.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- 
>> From: "k7fm" <k7fm at teleport.com>
>> To: <Gudguyham at aol.com>; <sm2ekm at telia.com>
>> Cc: <amps at contesting.com>
>> Sent: Wednesday, September 26, 2007 9:36 AM
>> Subject: Re: [Amps] IMD
>>
>>
>> > "AT highways speeds 55-70MPH you are  probably using
>> > less than a third of the total HP.  I guess it is kinda the  same thing
>> > HUH?"
>> >
>> > I disagree.  There is a local ham who, during calls to dx stations, 
>> > runs
>> > his
>> > amp into a region above where he should.  It is those peaks that cause
>> > terrible buckshot.  If the amplifier is tested at 600 watts, and the
>> > distortion level is rated at that level, then that is all it should be
>> > rated
>> > at - period.    Any power output above guaranteed linearity is
> worthless.
>> >
>> > Colin  K7FM
>> >
>> > _______________________________________________
>> > Amps mailing list
>> > Amps at contesting.com
>> > http://lists.contesting.com/mailman/listinfo/amps
>> >
>>
>>
>>
>> ------------------------------
>>
>> Message: 6
>> Date: Wed, 26 Sep 2007 16:37:01 +0200
>> From: "Peter Frenning [OZ1PIF]" <peter at frenning.dk>
>> Subject: Re: [Amps] How much electrolitic for a HV supply ?
>> To: Hamilton Horta - PY2NI <py2ni at terra.com.br>
>> Cc: amps at contesting.com
>> Message-ID: <46FA6E8D.7090507 at frenning.dk>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Hamilton Horta - PY2NI skrev:
>> >     Thanks a lot Peter, these figures are very close to what I thought,
>> > actually
>> > I was tempted to try (not in a definitive way but just run some tests)
> with
>> > something around 6,7uF (7x 47uF in parallel) but only for the amp with
> just
>> > one GI-7B. My feeling is that it?s going to prove me  I am wrong :)
>> >
>> > 73
>> > Horta
>> > PY2NI
>> >
>> >
>> You can see how I,ve done it here:
>> http://www.frenning.dk/OZ1PIF_HOMEPAGE/FL2000-QB.htm
>>
>> -- 
>> Vy 73 de OZ1PIF/5Q2M, Peter
>>
>> ** CW: Who? Me? You must be joking!! **
>> email: peter(no-spam-filler)@frenning.dk
>> http://www.frenning.dk/oz1pif.htm
>> Ph. +45 4619 3239
>> Snailmail:
>> Peter Frenning
>> Ternevej 23
>> DK-4130 Viby Sj.
>> Denmark
>> ***********************************
>>
>>
>>
>> ------------------------------
>>
>> Message: 7
>> Date: Wed, 26 Sep 2007 07:53:22 -0700
>> From: Steve Katz <stevek at jmr.com>
>> Subject: Re: [Amps] IMD
>> To: jeremy-ca <km1h at jeremy.mv.com>, amps at contesting.com
>> Message-ID:
>> <C770317F90C7CE45B0C92E844FB89BD2CBBE60 at mail05.corp.jmr.com>
>> Content-Type: text/plain
>>
>> Carl,
>>
>>
>>
>> The AL-572 uses four 572Bs, not three, and is rated 1300W PEP; however
>> that's not its key-down CW rating.   At 325W rated PEP output per tube,
> it's
>> rated exactly at the Cetron spec limit.
>>
>>
>>
>> 73
>>
>>
>>
>> Steve WB2WIK/6
>>
>>
>>
>>   _____
>>
>> From: jeremy-ca [mailto:km1h at jeremy.mv.com]
>> Sent: Tuesday, September 25, 2007 5:06 PM
>> To: Steve Katz; amps at contesting.com
>> Subject: Re: IMD
>>
>>
>>
>>  >If you look at the AL-1200 specs they claim 1200W with 3 tubes so no
>> matter how anyone wants to spin it Im not doing anything different at 
>> 750W
>> with two.<
>>
>>
>>
>> ::The AL-1200 uses a single 3CX1200A7 and runs 1500W output using a tube
>> having 1200W anode dissipation.  You must have a very different AL-1200.
>>
>>
>>
>> 73, Steve WB2WIK/6
>>
>>
>>
>> Sorry, I meant the AL-572 which you could just as easily have found by
> going
>> a bit further on their web site.
>>
>>
>>
>> Carl
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> ----- Original Message ----- 
>>
>> From: Steve Katz <mailto:stevek at jmr.com>
>>
>> To: Gudguyham at aol.com <mailto:Gudguyham at aol.com>  ; la7sl at online.no
>> <mailto:la7sl at online.no>  ; amps at contesting.com
> <mailto:amps at contesting.com>
>> ; km1h at jeremy.mv.com <mailto:km1h at jeremy.mv.com>
>>
>> Sent: Tuesday, September 25, 2007 4:37 PM
>>
>> Subject: RE: [Amps] 6 mtrs:
>>
>>
>>
>> Yep, things do change.
>>
>>
>>
>> I want to see the spectral analysis of the SB-200 (monoband or otherwise)
>> operating at 750W PEP output on SSB, closing in on IM3-5-7 especially.
>>
>>
>>
>> When I've used this tube, it's provided only about 8 dB power gain.  With
>> 100W drive that's <750W output, at any frequency.  The Cetron "ratings"
> per
>> the old data sheet I have is 30 MHz max for full ratings; 7.5 dB gain;
> 2.4kV
>> max and 250mA max per tube, yielding 300W output per tube (the data
>> obviously assumes 50% efficiency).  At even 65% efficiency to achieve 
>> 750W
>> out would be 1153W in, and 403W dissipation from a pair of tubes rated 
>> for
>> 320W max dissipation at 30 MHz.
>>
>>
>>
>> I fully agree anything's possible.
>>
>>
>>
>> WB2WIK/6
>>
>>
>>
>>
>>
>>
>>   _____
>>
>>
>> From: Gudguyham at aol.com [mailto:Gudguyham at aol.com]
>> Sent: Tuesday, September 25, 2007 1:28 PM
>> To: stevek at jmr.com; la7sl at online.no; amps at contesting.com;
> km1h at jeremy.mv.com
>> Subject: Re: [Amps] 6 mtrs:
>>
>>
>>
>> In a message dated 9/25/2007 12:36:55 P.M. Eastern Daylight Time,
>> stevek at jmr.com writes:
>>
>> But driving a pair of 572B's to 750W output  looks to a retired E
>> professional
>> like pushing an old VW beetle to 100MPH would look to an auto engineer:
>> Risky,- at best :-)
>> May be I am too conservative ??? ...
>>
>> Hi Steve, the Sb-200 operators manual says that 100 watts is permissible,
>> Just because you are used to an SB-200 on HF or similar amplifier that
> with
>> 100 watts makes only about 650 watts out, then why is the same 100 watts
> of
>> drive any different on 6 meters?  To me, 100 watts drive is 100 watts
> drive
>> either on 80 meters or 6 meters.  I think some of you guys have to think
>> "outside the box".  When one fine tunes a design and makes it specific 
>> for
> a
>> specific frequency we are talking a horse of a different color than an 
>> all
>> band amplifier.  Things change.
>>
>>
>>
>>
>>   _____
>>
>>
>> See what's new at AOL.com <http://www.aol.com?NCID=AOLCMP00300000001170>
>> and Make AOL Your
>> <http://www.aol.com/mksplash.adp?NCID=AOLCMP00300000001169>  Homepage.
>>
>>
>>
>> ------------------------------
>>
>> Message: 8
>> Date: Wed, 26 Sep 2007 10:57:57 -0400
>> From: "Tom Rauch" <w8ji at contesting.com>
>> Subject: Re: [Amps] IMD
>> To: <amps at contesting.com>
>> Message-ID: <007c01c8004d$a4bf9580$640fa8c0 at radioroom>
>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>> reply-type=original
>>
>> >> I disagree.  There is a local ham who, during calls to dx
>> >> stations, runs
>> >> his
>> >> amp into a region above where he should.  It is those
>> >> peaks that cause
>> >> terrible buckshot.  If the amplifier is tested at 600
>> >> watts, and the
>> >> distortion level is rated at that level, then that is all
>> >> it should be
>> >> rated
>> >> at - period.    Any power output above guaranteed
>> >> linearity is worthless.
>> >> Colin  K7FM
>>
>>
>> > Thats a bunch of BS as usual from you.
>>
>> Why is that line necessary in a technical exchange? IMO he
>> was making a valid point.
>>
>>
>> > Any decent commercial amp will do more than its advertised
>> > at. Its called
>> > overhead and allows for tube aging. Using you distorted
>> > logic (pun intended)
>> > an AL-1500 cant be run over 1500W otherwise you will have
>> > a poor signal.
>>
>>
>> Please check this link:
>>
>> http://www.ameritron.com/man/pdf/AL-1500.pdf
>>
>>
>> If we actually read the specs, it was tested in excess of
>> 2500W PEP in a two tone test. The IM3 at that level was
>> better than -34dB from one tone of the two. That's -40dB PEP
>> (crummy ARRL method).
>>
>> It is a little cleaner at 1500W, but not much.
>>
>> By the way the tested IM3 was worse case drive level using
>> two isolated exciters through a combiner rather than a sweet
>> spot caused by using a typical radio nto the amp. It is
>> possible if you raise and lower power (especially using a
>> regular radio as a test generator) to find "sweet spots"
>> where certain IM products are better over a narrow range.
>> Many systems don't follow a classic 3:1 IM vs. carrier level
>> change. In other words if you increase carrier power by 1 dB
>> IM should increase 3dB, but that doesn't often work in real
>> systems.
>>
>> If someone is measuring IM using a radio that has IM
>> anywhere remotely close to the PA IM levels, then they are
>> fooling themselves. They aren't measuring anything. It takes
>> an exceptionally clean source to obtain accurate data, and
>> you won't find that in a modern radio (although a class A
>> FT1000MP MKV kept well out of ALC gets close).
>>
>> I also have the opinion that IM should be determined at the
>> maximum specified or expected power, not some lower number.
>>
>> 73 Tom
>>
>>
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>> End of Amps Digest, Vol 57, Issue 52
>> ************************************
>>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>
> -- 
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> Checked by AVG Free Edition.
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